Hydrogen and methane production from household solid waste in the two-stage fermentation process

Area of Science:

• Biotechnology
• Environmental Science
• Waste Management

Background:

• Household solid waste presents a significant disposal challenge.
• Efficient energy recovery from waste is crucial for sustainability.
• Previous methods for biogas production often involve single-stage processes.

Purpose of the Study:

• To demonstrate a successful two-stage process for sequential hydrogen and methane production from household solid waste.
• To optimize hydrogen production conditions and evaluate methane yield enhancement.
• To investigate the impact of process parameters on fermentation pathways.

Main Methods:

• A two-stage anaerobic digestion system was employed.
• The first stage focused on hydrogen production, followed by methane production in the second stage.
• Process parameters including pH, hydraulic retention time, and gas sparging were controlled and monitored.

Main Results:

• Hydrogen yield reached 43 mL H(2)/g volatile solid (VS).
• Methane yield achieved 500 mL CH(4)/g VS, a 21% increase over the one-stage control.
• Methane sparging doubled hydrogen production; optimal pH for hydrogen production was 5-5.5.
• Short hydraulic retention time (2 days) effectively separated acidogenesis from methanogenesis.

Conclusions:

• The two-stage process is effective for maximizing energy recovery from household solid waste.
• Process control, particularly pH and gas sparging, significantly influences hydrogen and methane yields.
• This approach offers a viable strategy for enhanced biogas production and waste valorization.